25 May – Saint Urban I

Hall of Constantine

Modern Hagiography

Roman Martyrology

Sanctorale Catholicum

Lives of the Saints by Alban Butler.

Lives of the Saints by Sabine Baring-Gould.

The Liturgical Year by Dom Guéranger.

The Lives of Saints, with Other Feasts of the Year, According to the Roman Calendar by Peter Ribadeneira.

La vie des saints

Medieval Hagiography

BHL, Supplement

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

Liber pontificalis 

The Golden Legend (and illustrations)

Art & Architecture

Index of Medieval Art

Catalogo generale dei beni culturali

BeWeB

Europeana

Portail Biblissima

POP : la plateforme ouverte du patrimoine

16C Fresco of Saint Valerian and Pope Urban

Warburg Institute Iconographic Database

Sant’Urbano alla Caffarella

Sistine Chapel, South Wall

in situ
Die Sixtinische Kapelle
Post-Biblical Saints Art Index
Saints and their Attributes

A Garner of Saints: Being a Collection of the Legends and Emblems Usually Represented in Art by Allen Hinds.

The Saints in Art by Joseph Maria von Radowitz.

Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.

See also 22 November – Saint Cecilia.

Music

Cantus: A Database for Latin Ecclesiastical Chant